Method for mining material from the entire face



United States Patent inventors Appl. No. Filed Patented Assignee METHODFOR MINING MATERIAL FROM THE ENTIRE FACE 6 Claims, 16 Drawing Figs.

US. Cl 299/18 Int. Cl E2lc 27/24 Field ofSearch 299/10, 11, 18, 64, 75,76

References Cited UNITED STATES PATENTS 2/1903 Pawe] 299/75X PrimaryExaminer-Ernest R. Purser Attorney-David Young ABSTRACT: A method ofmining material from the entire mine face with a rotary mining head thathas hemiovate ends. The rotary mining head is advanced into the mineface for a major part of the head, and traversed through the material ofthe mine face to cut and break the material out of the mine face. Thisleaves cusps of material behind the rotary mining head. The mining headis retreated to the cusps of material, which are removed by traversingthe rotary mining head through the cusps of material. This iasttraversing movement positions the rotary mining head for the nextadvance into the mine face and the next mining operation.

Patented Nov. 24, 1970 /N\/EN7'O/?S; WILLIAM EM CRACKEN, FAY E MUNGER'BY MLW ATTORNEY Patented Nov. 24, 1970 Sheet HTTORNEY Patented Nov. 24,1970 3,542,432

WILCIAM EM CRACKEN, FAY EMUNGER ATTORNEY Patented Nov. 24, 19703,542,432

l v ||ly \v" 7 v v I 'Fi. 83 32 Bi 10 INVh'N'IUR-i; WILLIAM E.M CRAQKEN,FSY EM GER BY ATTORNEY Patented Nov. 24, 1970 3,542,432

METHOD FOR MINING MATERIAL FROM THE ENTIRE FACE The instant inventionrelates to a method ofmining for mining material from the entire areaofthe mine face ahead of the mining machine.

In typical underground mining operations the material is mined from themine face by a cutting and breaking action. The mining machine advancesforwardly in the direction of the mine face to penetrate the face forthe cutting and breaking action. It is a fundamentalobjective to minethe material at the highest rate, which is reflected in the rate ofadvance of the mining machine. The higher is the rate that the materialis removed from the mine face, the higher is the rate of advance ofthemining machine.

The mining machine customarily has a mining head at its forward end,which is sumped into the mine face and mines the material by cutting andbreaking. After the mining head is operated over the entire face area,the mining machine is advanced to again sump the mining head into themine face and the operation is repeated. lt is desired that thesuccessive steps of advance be performed on a continuing basis, and therate at which the material is mined from the mine face determines therate at which the mining machine can be advanced for the successivesteps ofmining the material.

Another factor that affects the rate of advance ofthe mining machine isthat of roof control. It is a serious problem in underground miningoperations that as the mine face is advanced there is produced anexposed roof which was formerly supported by the material that has beenmined from under the roof. This gives rise to the possibility of rooffalls. Due to the nature of the geological strata, roof falls mayinvolve tons of material. such as slate and rock, with the potential tocause personal injury and damage to the equipment. Therefore, great careis taken in underground mining operations to control the roof, with thepurpose practical, avoid falls, and this is even subject to governmentregulations having the force of law.

In mining operations the roof may be controlled by the use of posts orprops set between the floor and the roof as a substitute for the minedmaterial, to provide vertical support. Another form of roof control istimbering in which timbers are set vertically, usually at the oppositeribs, and another timber is laid across the top of the upright timbersimmediately below and bearing up against the roof. Wedges are driven into force the cross timber against the roof in close contact to providevertical support. Still another form of roof control is by roof boltingin which bolts with long shanks, of the order of 3 feet to 4 feet inlength, are driven in above the roof and a plate is laid against theroof and held in place by a nut that is turned on the bolt. Roof boltingis advantageous because it permits greater flexibility in the placementof the roof supports than is the case with timbers, the roof bolts haveconsiderably less bulk than the timbers, and therefore are easier tohandle and do not occupy as much space as the timbers. The principle ofroof bolting is to tie the strata immediately above the roof to moresecure strata, thereby supporting the lower strata from higher firmerstrata.

Any of the roof control systems are nonproductive in nature, in thatthey do not directly produce mined material. The

roof control procedures interrupt the actual mining operation, since themining machine is stopped to permit roof supports to be installed. It isa limiting factor that the mining machine may not advance beyond a givendistance under unsupported roof. Therefore, when the mining machine isadvanced through this distance it must be stopped until roof supportsare installed. Then the mining machine may resume its advance throughthe given distance, at which time there is another shutdown while theroof supports are placed. The distance that a mining machine may advanceunder an unsupported roof is usually relatively short, so that theproduction of the machine is materially affected by the necessaryinterruptions to install roof supports, and it is not possible torealize the full production capacity of the machine.

g The mine face presents a face area which is bounded by the floor atthe bottom, the roof at the top, and the ribs at the opposite sides,from which the material is :mined. it is desired to remove the greatestvolume of material from the mine face. Consonant with this objective thecorners of the mine face would be cut square, to mine all the materialbetween the boundaries of the floor, roof and opposite ribs. However,the square cut corners at the roof produce a poor condition from thestandpoint of roof control. The roof control is improved in the case ofboring machines which have large circular boring heads that advance intothe mine face in the direction of the axes of the circular boring heads.The boring heads produce an arcuate configuration ofthe roof at eachrib, which is a portion of the circle of the boring head. The physicaleffect of such arcuate configuration of the roof at each rib is similarto that in an arch'in which the arch is self-supporting. However, theroof that is produced by the boring machines is not totallyself-supporting, but there is a large measure of additional support forthe roof stemming from the arched or curved configuration at the ribs.With this added measure of roofsupport it is possible to advance themining machine through greater distances than would otherwise be thecase before the machine is stopped for the installation of roofsupports. This permits uninterrupted operation ofthe mining machineduring longer periods of time, and materially improves the efficiency ofthe mining operation.

The boring type mining machine characteristically has a mining headwhich covers with entire face area. The mining head includes thecircular boring heads and trimming cutting chains or trimming cuttingbars which span the distance between the circular boring heads where thelatter do not overlap. These trimming cutting chains or cutter barsprovide a flat floor surface for the advance of the mining machine.

In another type of mining machine there is a rotary mining head which isconsiderably smaller than the area of the mine face from which thematerial is mined. The mode of operation is to sump the mining head intothe material of the mine face, and then to traverse the mining headthrough the material to cut and break the material out of the mine face,and then to traverse the mining head through the material to cut andbreak the material out of the mine face, and this manner to cover theentire area of the mine face between the roof, floor and the oppositeribs. Such a mining machine is illustrated in the patent to JamesKilbourne, US. Pat. No. 3,305,273,

Feb. 21, l967, for Mining Apparatus Supporting and Driving Construction.The rotary mining head of the patent has a plurality ofcutting bitsdisposed in a cylindrical form, which in the course of operating themining machine produce square corners at the junctions of the roof withthe opposite ribs. While this form of cutting head is effective toremove the greatest volume of material from the entire face area, it isnot most satisfactory for roof control. This condition is improved by arotary cutting head which has its opposite ends with a hemiovate form toform the roof with a curved or arched portion at each rib.

In mining the material it is desired to advance the rotary mining headinto the mine face to the greatest depth that is practical, so that inthe course of traversing the mining head through the mine face thecutting depth will be great, thereby cutting and breakinga greatervolume of material out of the mine face during the traverse. The mininghead that is formed with the hemiovate ends any be advanced into themine face for a major part of the diameter of the head, but this leavesa substantial sized cusp of material on each rib during the traverse ofthe mining head. Such cusps on the ribs reduced the lateral clearancebetween the ribs, and. therefore, are undesirable. The improved methodof mining the material with the rotary mining head provides a sequenceof steps for mining the material that includes the removal of the cuspsfrom the ribs, so as to provide the full width of lateral clearancebetween the ribs for movement of the mining machine.

Accordingly, it is an object of this invention to provide an improvedmethod of mining material, in which the rotary mining head may beadvanced into the mine face for a major part of its diameter, in orderto increase the rate of removal of material during the traverse of themining head through the material.

It is also an object of the invention to provide an improved 7 method ofmining material with a rotary mining head in which the mining head isadvanced into the material and cuts and breaks out the material during atraversing movement of the mining head, and removes thecusps ofamaterial from the ribs by another traversing movement of the mininghead.

It is still another object of the invention to provide an improvedmethod ofmining material with a rotary mining head that has hemiovateends, in which a major part of the rotary mining head is advanced intothe material and traversed through the material to cut and break out thematerial, during which cusps of material are left on the opposite ribs,and such cusps are removed from the ribs by another traversing movementofthe mining head at a retreated position.

It is a further object ofthe invention toprovide an improved method ofmining material with a rotary mining head in which .a cusp of materialon the floor may be removed.

Other objects of the invention will appear hereinafter, the novelfeatures and combinations being set forth in the appended claims.

In the drawings:

FIG. 1 is a side elevation of a mining machine in accordance with theinvention;

FIG. 2 is a plan view ofthe mining machine;

FIG. 3 is a front elevation view of the rotary mining head with anoutline of the mine face area in which the material is mined; I

FIG. 4 is an end elevation view of the rotary mining head;

' FIGS. 5 and 6 are elevation and plan views, respectively, showing theposition of the rotary mining head at the mine face; I

FIGS. 7 and 8 are elevation and plane view, respectively, showing theposition of the rotary mining head advanced into the mine face;

FIGS. 9 and 10 are elevation and plan views respectively, showing therotary mining head at the end of its traversing movement;

FIGS. 11 and 12 are elevation and plan views, respectively, showing theretreated position of the rotary mining head after removing the floorcusp;

FIGS. 13 and 14 are elevation and plan views, respectively, showing theretreated position of the rotary mining head prior to removal of the ribcusps; and

FIGS. 15 and 16 are elevation and plan views, respectively, showing theposition of the rotary mining head after removal of the rib cusps andprior to the next advance into the mine face.

Referring to the drawings, there is illustrated in FIGS. 1 and 2 amining machine 10 in accordance with the invention, supported on endlesstraction treads 11,12 at opposite sides by which the machine inpropelled. At the forward end of the mining machine 10 there is a rotarymining head 13, on a transverse axis, to be advanced or sumped into themine face 14, and traversed through the material of the mine face, tomine material from the entire face area by a cutting and breakingaction. The mining head 13 is supported on the forward end of a boom 15by which it may be raised to the roof l6, sumped into the material ofthe mine face 14, and traversed through the material downwardly to thefloor 16. The mining head 13 extends transversely between the oppositeribs 18,19 and the latter define the side boundaries of the face areathat is mined by the mining head 13,

The boom 15 is connected to the mining machine main frame 20 ontransverse pivots 21,22 on which the boom 15 is swung upwardly anddownwardly by cylinders 23,24 connected between the mainframe 20 and theboom 15.

The mining machine 10 is powered by motors 25,26 on opposite sides oftheboom 15. Driving connections 27,28 extend forwardly from motors 25,26,respectively, to transmissions 29,30, at opposite sides of the boom 15,from which the mining head 13 is driven. US. Pat. No. 3,305,273illustrates in detail a form of the driving connections andtransmissions by which the mining head 13 may be driven, in which thepower of both motors 25,26 is delivered to the entire mining head 13,

The motors 25; 26 also provide power for driving traction threads 11,12.Drive connections 31,33 extend rearwardly from motors 25, 26,respectively to transmissions 33,34 at 0pposite sides ofthe main frame20 for delivering the drive to the traction treads 11,12.

In the mining operation the material cut and broken out of the mine face14 falls to the floor 17. There is a gathering head at the front of themining machine 10. below the boom 15, The gathering head 35 has an apronor deck 36 with its leading edge at the floor 17. Gathering arms 37,38at opposite sides of the gathering head 35 operate with an oscillatingmotion to reach down and to sweep the material into a conveyor 39 whichextends longitudinally through the mining machine 10 from the gatheringhead 35 to the discharge boom 40 at the rear end of the mining machine10. The conveyor 39 moves the mined material from the forward end ofmining machine 10 to its rear end at which it is discharged to conveyingapparatus for removing the mined material from the mining place. Thegathering arms 37,38 are powered by the motors 25,26. Drivingconnections 41,42 extend forwardly from transmissions 33,34 respectivelyto gathering head transmissions 43,44, from which the gathering arms 37,38 are driven.

In FIG. 3 there is a front elevation view of the rotary mining head 13.There is an intermediate section of the mining head 13 with spiralflights 51,52 at diametrically opposite positions, and additional spiralflights 53,54. Several cutting bit holders 55,55 are secured at spacedpositions on the peripheries of the spiral flights 5152,5354. A cuttingbit 56 is releasably secured in each holder 55. The cutting bits 56 andtheir holders 55 are disposed at spaced positions in the circumferentialdirection and in the axial direction of the mining head 13, such thatwhen the mining head 13 rotates, the cutting bits 56, 56 sequentiallyengage the material of the mine face at several positions across themine face.

At the left side of the intermediate section 50 of the mining head 13,as viewed in FIG. 3, there is a cutting chain 58 extending around a gearcase 57 at the forward end of the boom 15, that may be constructed inthe manner of US. Pat. No. 3,305,273. The path of cutting chain 58 iscoincident with a major part of the circumference of the mining head 13,as best seen in FIG. 4. The chain 58 has a plurality of links 59,59 withconnecting links 60,60, and articulated connections including pins61,61. The pins 61, 61 project from the opposite sides of the chain 58to be engaged by a sprocket 62 on the intermediate mining head section50 at one side of the chain 58, and another sprocket 63 at the otherside of the cutting chain 58, which is secured to the outer mining headsection 65. The sprockets 62,63 rotate with the mining head 13 and byengagement with the outer ends of pins 61,61 of the cutting chain 58drive the latter concurrently with the rotation of the mining head 13,which may be generally in the same manner as in US. Pat. No. 3,305,273.

A plurality of cutting bit holders 55 are secured to the links 59,60 ofcutting chain58 at spaced positions along and across the latter toprovide a pattern of cutting bits 56,56 in which they sequentiallyengage the material of the mine face 14 at spaced positions across theface, as the cutting chain 58 is moved by rotation ofthe mining head 13.

The mining head 13 has an outer mining head section 65 at the left side,as viewed in FIG. 3, outboard ofthe cutting chain 58. Spiral flights66,67 are wound on one part of the mining head section 65atdiametrically opposite positions, and spiral flights 68,69 are woundon another part of the mining head section 65 as continuations of thespiral flights 66,67 respectively. A plurality of cutting bit holders 55with their cutting bits 56, are secured to the outer mining head section65 on the spiral flights 66,67,68,69 69 at circumferentially and axiallyspaced positions to sequentially engage the material of the mine face 14at spaced position across the latter during rotation of the mining head13.

Beyond the outer mining head section 65 there is an end mining headsection 70 as an axial extension of section 65. End section 70 isconnected to section 65 by a telescoping cylinder part 71 that may beextended and retracted relatively to section 65. The inner portion ofthe end section 70 in the area of telescoping cylinder part 71 hasspiral flights 72,73 wound at diametrically opposite positions ascontinuations of spiral flights 68,69 respectively, when end section 70is extended, as illustrated in FIG. 3. Several cutting bit holders 55and their bits 56 are secured at spaced positions on spiral flights72,73 to sequentially engage the material of the mine face 14 at spacedpositions across the latter. Beyond the spiral flights 72,73, there is acollar 74 and an end cap 75 which are of successively lesser diameterstowards the outer end of the end section 70. A plurality of cutting bitholders 55 and their bits 56 are secured to the collar 74 and to the endcap 75 at spaced positions in the circumferential and axial directionsto sequentially engage the material ofthe mine face 14 at spacedpositions across the latter. The disposition of the cutting bits 56 isbest seen in FIGS. 3 and 4.

At the right side of the intermediate mining head section 50 there isanother cutting chain 58 like the cutting chain 58, but oppositelydisposed, and such cutting chain 58' and its parts are identified by thesame reference numerals, with the addition of a prime The right side ofthe mining head 13, as seen in FIG. 3, is the same as the left side, butthe elements are oppositely disposed. The elements of the right side ofthe mining head 13 are identified by the same reference numerals asapplied to the elements at the left side with the addition of a prime toeach reference numeral, and the description of the left side of themining head 13 applies also to the right side ofthe mining head. i

The cutting bits 56,56 on the intermediate mining head section 50 and onthe outer mining head sections 65,65 are all at the same radius, and inrotating the mining head 13 these cutting bits 56,56 move in the form ofa cylinder. Likewise, the cutting bits 56,56 on the cutting chains58,58'58 are disposed at the same radius so that they also move in thesame cylindrical form in the portion of their paths which coincide withthe mining head These cutting bits 56,56 moving in the cylindrical form,develop a flat intermediate surface 78 on the roof 16 and a flatintermediate surface 79 on the floor 17. Beyond the outer mining headsections 65, 65', the cutting bits 56,56 which are on the end mininghead sections 70,70, are at positions of decreasing radial distancestowards the outer end of the mining head 13. In the rotation of themining head 13, the cutting bits 56,56 on the end mining head sections70,70 move in a hemiovate form and produce curved or arched surfaces80,81 on the roof 16 downwardly to the rib 18. Similarly, the floor 17is formed with a curved surface 82 up to the rib 18 and curved surface83 up to the rib 19. However, the flat intermediate surface 79 on thefloor 17 is of sufficient width to accommodate the opposite tractiontreads 11,12 as seen in FIG. 3, for movement ofthe mining machine on aflat part ofthe Hour 17.

In FIG. 3 the total cutting profile ofthe mining head 13 is illustratedby the phantom perimetal line 85. The profile line 85 illustrates theequal radial distances ofthe cutting bits 56,56 of the intermediatemining'head section 50, of the outer mining head sections 65,65, and ofthe cutting chains 58,58, and the decreasing radial distances of thecutting bits 56,56 on the end mining head sections 70,70which form thehemiovate end sections of the mining head 13. At each extreme end of themining head 13, the cutting bits 56, 56 are in a crown disposition, asbest seen in FIGS. 3 and 4, and provide flattened ends of the oppositehemiovate sections of the mining head 13, to cut the ribs 18,19.

As illustrated herein, and particularly with reference to FIGS. 1 and 4,the mining head 13 is rotated in the clockwise direction so that thecutting bits 56,56 engage the material in the mine face 14 in adescending direction. As viewed in FIG.

3, the cutting bits 56,56 move downwardly from top to bottom of theprofile line 85. The removal of the material from the mine face 14 is acutting and breaking action in which the cutting bits 56,56 cut into thematerial, and concurrently, the cutting bits along with the severalspiral flights break the material out ofthe mine face and it falls tothe floor 17.

Referring to FIGS. 5 and 6, the rotary mining head 13 is positioned atthe top ofthe mine face 14 by swinging the boom 15 upwardly to the roof16. The first step in the mining method is to advance the rotary mininghead 13 into the mine face 14, which is the sumping movement of themining head 13. This is illustrated in FIGS. 7 and 8 wherein it is seenthat the rotary mining head 13 has been moved along the roof 16 into thematerial of the mine face 14. This exposes a new portion of the roof 16along a line or level that is a continuation of the roof 16 that hasbeen previously exposed. The mining head 13 rotates as it is advancedinto the mine face 14 so that the material is cut andbroken out of themine face 14 during such advance. This material falls to the floor 17where it is collected by the gathering arms 37,38.

The depth of advance of the rotary mining head 13 into the mine face 14determines the volume of material that is removed during traversingmovement of the mining head 13. Therefore, it is desired to. advance themining head 13 to the greatest depth practicable, in order to increasethe rate of mining removal of material. As illustrated in FIG. 7, therotary mining head 13 may have a diameter of 36 inches (36" and a majorpart of the mining head 13 is advanced into the mine face, which may bean advance of 30 inches (30"). As seen in FIG. 8, the hemiovate ends ofthe mining head 13 do not completely overlap or engage the materialofthe mine face 14. When the mining head 13 is traversed through thematerial of the mine face 14 downwardly towards the floor 17, asillustrated in FIG. 9 and 10, cusps of material 90,91 are left on theribs 18,19 respectively, behind the mining head 13. By reason ofthecircular form of the mining head. 13, there is also a cusp ofmaterial 92which remains on the floor.

The rotary mining head 13 is then retreated along the floor 17 to theposition illustrated in FIGS. 11 and 12, which removes the cusp ofmaterial 92 from the floor 17. The rotary mining head 13 is then movedto the position illustrated in FIGS. 13 and 14, in which the axis of themining head 13 is alined with the center lines of the cusps of material90,91 on the ribs 18,19 respectively. This is another retreated positionof the mining head 13, so termed because the mining head 13 is disposedrearwardly away from the newly exposed mine face 14.

The rib cusps of material 90,91 are removed by traversing the rotarymining head 13 upwardly to the roof 16 by swinging the boom 15 upwardly.The crown ends of the rotary mining head 13 are of substantially thesame width as the base width of the rib cusps of material 90,91, so thatthe crown ends of the mining head 13 meet the cusps 90,91 and remove thelatter during the upward traverse of the mining head 13. This thenplaces the mining head 13 at the roof 16, as seen in FIGS. 15 and 16.The mining head 13 may then be advanced along the line of the roof 16 tosump the mining head 13 into the mine face 14, in the manner illustratedin FIGS. '7 and 8, for the next sequence of the steps of the method ofmining, as has been described above.

The method ofmining provides a sequence of steps with the rotary cuttinghead 13, by which the several movements of the mining head 13 occur insequence to cut and break the material out of the mine face .14,followed by the removal ofthe floor cusp of material 92, and the ribcusps of material 90,91, and positioning the mining head 13 at the roof16 for the next step of advancing the mining head 13 into the mine face14 for the next sequence of steps. As illustrated herein, the mine face14, the roof 16, the floor 17, and the ribs 18,19 are shown as niceregular and clean surfaces. However, it will be understood that theillustrations are representations of the respective surfaces, and inpractice it occurs that the exposed surfaces in the mine are rough sincethe material is cut and broken out of the mine.

Thus, for example, after the removal of the rib cusps, the rib surfacesare clean by mining standards, but there may still remain some roughnessor irregularity of material on the ribs 18,19 due to the nature ofthemining operation and the fact of working with geological strata. Also,it may be unnecessary to remove the floor cusp 92 with the rotary mininghead 13, as described above, since it sometimes occurs that the materialat the floor 17 is not bound very firmly in place, and such material maybreak loose simply by the bulldozing action ofthe front edge of thegathering head deck 36.

We claim:

1. A method of mining material from a mine face with a transverse rotarymining head that has a hemiovate form at each end of the mining head,said mine face being bounded by a roof at the top, a floor at thebottom, and by a rib at each side. comprising the steps of advancing amajor part ofsaid rotary mining head into the material of the mine face,traversing said rotary mining head through the material of the mine facebetween said roof and said floor and leaving cusps of material on saidrib behind the mining head along the path of the traverse, rotating saidrotary mining head and cutting and breaking material out of the mineface as the rotary mining head is advanced into the mine face and as therotary mining head is traversed through the material of the mine facebetween said roof and said floor, retreating said rotary mining head tosaid cusps of material on said rib, and traversing said rotary mininghead between said floor and said roof and along said cusps on said ribto remove the material of the cusps from said rib.

2. A method of mining material from a mine face as recited in claim 1,said cusp of material remains on each rib as the totary mining head istraversed through the material ofthe mine face. and traversing saidrotary mining head through said cusp of material on each rib upwardlyfrom the floor towards the roof.

3. A method of mining material from a mine face as recited in claim 1,retreating said rotary mining head to the position of said cusps ofmaterial, and traversing said rotary mining head through the cuspsofmaterial from the floor towards said roof.

4. A method of mining material from a mine face with a transverse rotarymining head that has a hemiovate form at each end ofthe mining head,said mine face being bounded by a roof at the top, a floor at thebottom, and by a rib at each side, comprising the steps of advancing amajor part of said rotary mining head into-the material ofthe mine faceat the roof, traversing said rotary mining head through the material ofthe mine face down to the floor and leaving cusps of material on theribs behind the mining head along the path of traverse from the roofdown to the floor, rotating said rotary mining head and cutting andbreaking material out of the mine face as the rotary mining head isadvanced into the mine face and as the rotary mining head is traversedthrough the material of the mine face from the roof down to the floor,retreating said rotary mining head to said cusps of material on theribs, and traversing said rotary mining head up to the roof and alongsaid cusps of material on the ribs to remove the material of the cusps.

5. A method of mining material from a mine face as recited in claim 4,retreating said rotary mining head along the floor to said cusps ofmaterial on the ribs, and traversing said rotary mining head from thefloor to the roof along said cusps of material to remove the materialofthe cusps.

6. A method of mining material from a mine face as recited in claim 4,traversing said rotary mining head upwardly to the roof along said cuspsof material to remove the material of the cusps, and placing said rotarymining head at the roof in position to be advanced along the roof andinto the material of the mine face.

